Why sanctions on Iran are not serious

Sanctions rarely work. They are even less likely to impose a significant cost on a country when other neighboring countries aren't interested in imposing sanctions. If Russia, China, and other countries are refusing to participate, what chance do these sanctions have? From VOA:

Iran and its powerful ally Russia have denounced new Western sanctions on Tehran's financial, petrochemical and energy sectors, calling them illegal and futile.

The U.S., Canada, and Britain each announced new steps Monday to increase economic pressure against Iran in response to international concerns that Tehran is developing nuclear weapons.

Iranian Foreign Ministry spokesman Ramin Mehmanparast said Tuesday the unilateral measures by the the three countries amounted merely to "propaganda and psychological warfare." He predicted they would prove ineffective, saying Iran's trade and economic ties with the U.S. and Britain are small anyway.

Separately, Russia's foreign ministry called the sanctions "unacceptable and contradictory to international law." Moscow, together with Beijing, has blocked further punitive measures against Tehran from reaching the United Nations Security Council for approval. Four rounds of U.N. sanctions against Iran have already been passed.

Washington said Monday it is imposing sanctions on goods and services used by Iran's oil and gas industry to discourage foreign companies from investing in the sector. The U.S. also announced a worldwide diplomatic campaign to encourage countries to buy petrochemicals from other suppliers. . .